Dieback of Austrian pine – the epidemic occurrence of Sphaeropsis sapinea in southern Moravia

Abstract

In the course of recent years, various cases of Austrian pine dieback of all age classes have occurred in a number of localities. At all localities, Sphaeropsis shoot – killing of pine caused by Sphaeropsis sapinea (Fr.) Dyko et Sutton syn. Diplodia pinea (Desm.) Kickx. was recorded on a mass scale in declining shoots. Fruit bodies of the fungus were found on twigs, at the base of needles being particularly abundant on cones. Generally, the fungus is considered to be an opportunist pathogen which spreads on damaged tissues of shoots accelerating their dying. In trees with the same symptoms of damage, Brunchorstia pinea (Karsten) Höhn was also detected at some localities. The occurrence of scales Leucaspis pussila (Loew.) can be considered to be the demonstration of stress load of trees suffering from drought. Feeding marks of Pityophthorus pityographus (Ratzeburg) and Ips acuminatus (Gyll.) were noticed. Annual shoots were damaged by species of the genus Magdalis at some localities. The impact of climatic extremes, particularly drought the effect of which is also manifested in increments is an important predisposition factor. The situation under study is rather the result of a chronic damage to pine and secondary activation of some pathogens particularly of Sphaeropsis sapinea and pests which can occur as mortality stressors.